Menstrual Cramps (Dysmenorrhea): What are you hoping to get out of this — relief today, or an easier cycle next month?

Commonly suggested options include zinc, acupuncture, fenugreek, saffron (Crocus sativus), auricular Acupuncture and fennel.

Menstrual Cramps (Dysmenorrhea): When cramps take over, what kind of help feels right for you?

Commonly suggested options include fennel, ginger, fenugreek, curcumin, saffron (Crocus sativus) and boswellia.

Menstrual Cramps (Dysmenorrhea): natural remedies and the evidence behind them

14 options · 8 graded A · 2 graded B · 2 graded C · 2 traditional or ungraded

What are you hoping to get out of this — relief today, or an easier cycle next month?

I want to get ahead of it — make my next few cycles less painful

Zinc
Supported by controlled trials· Centuries of traditional use (Evidence grade A · Traditional use long-standing)Long-standing traditional staple
Mineral shown to ease period pain
Why it may be relevant
If you'd rather take something in, zinc is a simple mineral with pooled trial evidence for reducing menstrual pain.
Why try it
Zinc's anti-inflammatory and antioxidant actions may curb the prostaglandins and uterine spasms that drive cramping.
Dose or use
Commonly studied at roughly 30-50 mg daily, often started a few days before your period; follow product labeling and avoid exceeding about 40 mg long-term without guidance.
Time to results
Often within 1-2 cycles
Key study
Systematic Review & Meta-Analysis (2024, PMID 39683510): 'Efficacy of Zinc Supplementation in the Management of Primary Dysmenorrhea' pooled randomized trials and found zinc supplementation reduced menstrual pain severity.
Caution
Doses above about 40 mg/day long-term can deplete copper and upset the stomach; take with food and check with a clinician if you take other medications.
Acupuncture
Supported by controlled trials· Centuries of traditional use (Evidence grade A · Traditional use long-standing)Long-standing traditional staple
Needle therapy targeting pain and flow
Why it may be relevant
If you want a practitioner-led, body-based session, acupuncture is a traditional go-to for cycle pain.
Why try it
Traditionally used to regulate qi and blood flow, with the aim of easing uterine cramping and tension.
Dose or use
Work with a qualified, licensed practitioner; ask them how many sessions and how often are right for you.
Time to results
Typically 2–3 cycles
Key study
Systematic Review & Network Meta-Analysis (2026, PMID 41056095): 'Acupuncture-Related Therapies for Primary Dysmenorrhea' pooled randomized trials and found acupuncture-related therapies reduced menstrual pain compared with control.
Caution
Seek a licensed acupuncturist; avoid certain points during pregnancy.
Fenugreek
Supported by controlled trials· Recognised traditional use (Evidence grade A · Traditional use recognised)Recognised traditional use
Seed herb for menstrual pain relief
Why it may be relevant
If you prefer an internal herbal remedy, fenugreek has a long traditional history of use for easing period cramps.
Why try it
Traditionally used to help relax uterine muscles and reduce the severity of menstrual cramping when taken orally.
Dose or use
Follow product labeling; consult a healthcare practitioner.
Time to results
Typically 1–3 cycles
Key study
Systematic Review & Meta-Analysis (2024, PMID 37594100): 'The Effect of Fenugreek on the Severity of Dysmenorrhea' pooled randomized trials and found fenugreek reduced the severity of menstrual pain.
Caution
Avoid medicinal doses during pregnancy; may lower blood sugar in people on diabetes medications.
Saffron (Crocus sativus)
Supported by smaller clinical studies· Recognised traditional use (Evidence grade B · Traditional use recognised)Recognised traditional use
Spice traditionally used for cycle support
Why it may be relevant
If you prefer taking something internally, saffron is a traditional herbal option historically used for menstrual comfort.
Why try it
Traditionally used to support smooth muscle relaxation and mood during the menstrual cycle.
Dose or use
Follow product labeling; consult a healthcare practitioner.
Time to results
Typically 2–3 cycles
Key study
Systematic Review & Meta-Analysis (2026, PMID 41151539): 'Effect of saffron on premenstrual syndrome and dysmenorrhea' pooled randomized trials and found saffron improved menstrual-cycle symptoms.
Caution
Avoid high doses during pregnancy; may interact with antidepressants.
Auricular Acupuncture
Centuries of traditional use· Limited human trials so far (Evidence grade C · Traditional use long-standing)Long-standing traditional staple
Ear-based acupuncture for cycle pain
Why it may be relevant
Another hands-on, practitioner-applied technique that fits if you're open to body-based treatments.
Why try it
Traditionally used to stimulate reflex points on the ear believed to correspond to the uterus and pelvic region.
Dose or use
Work with a qualified, licensed practitioner; ask them how many sessions and how often are right for you.
Time to results
Typically 2–3 cycles
Key study
Systematic Review & Network Meta-Analysis (2026, PMID 41056095): auricular techniques are included among the acupuncture-related therapies studied for primary dysmenorrhea, though ear-specific evidence is more limited and often bundled with body acupuncture.
Caution
Best performed by a trained practitioner; not well-studied in pregnancy.

I'm cramping right now — I need something that works today

Fennel
Supported by controlled trials· Centuries of traditional use (Evidence grade A · Traditional use long-standing)Long-standing traditional staple
Aromatic seed herb for cramp relief
Why it may be relevant
If you prefer an internal herbal option, fennel is an antispasmodic seed herb with solid trial support for period pain.
Why try it
Fennel's anethole and related compounds have antispasmodic effects that may relax uterine muscle and ease cramping.
Dose or use
Commonly taken as a fennel extract or tea around the start of your period; follow product labeling.
Time to results
Often within the first day or two of a period
Key study
Systematic Review & Meta-Analysis of RCTs (2020, PMID 33182553): 'Fennel for Reducing Pain in Primary Dysmenorrhea' pooled randomized trials and found fennel reduced menstrual pain intensity.
Caution
May interact with estrogen-sensitive conditions and blood thinners; talk to your doctor if pregnant or on hormone therapy.
Warm Compress
Supported by controlled trials· Centuries of traditional use (Evidence grade A · Traditional use long-standing)Long-standing traditional staple
Applied heat to soothe cramping muscles
Why it may be relevant
If you want something hands-on you can feel working right away, warmth on the lower belly is about as immediate as it gets.
Why try it
Traditionally used to relax the uterine muscles and ease cramping by bringing warmth and blood flow to the area.
Dose or use
Apply a warm pack or hot water bottle to your lower abdomen for 15-20 minutes as needed.
Time to results
Often eases discomfort within minutes
Key study
Systematic Review & Meta-Analysis (2025, PMID 41657584): 'Heat therapy for primary dysmenorrhea' found applied heat reduced menstrual pain intensity, in some trials comparably to NSAIDs.
Caution
Use a cloth barrier to avoid burns; don't apply heat to broken or numb skin.
Ginger
Supported by controlled trials· Centuries of traditional use (Evidence grade A · Traditional use long-standing)Long-standing traditional staple
Warming root herb used for period pain
Why it may be relevant
If you'd rather take something in, ginger is an easy kitchen-cupboard herb long reached for during cramping.
Why try it
Traditionally taken as tea, capsules, or fresh root to warm the belly and ease the intensity of period cramps.
Dose or use
Follow product labeling; commonly taken as tea or capsules from the start of your period.
Time to results
Often within the first day or two of use
Key study
Systematic Review & Meta-Analysis (2024, PMID 38770631): 'Ginger for Pain Management in Primary Dysmenorrhea' pooled randomized trials and found ginger reduced menstrual pain intensity versus placebo.
Caution
May thin the blood and lower blood sugar; use cautiously if on anticoagulants or diabetes medication.
SP6 (Sanyinjiao) - Spleen 6
Supported by controlled trials· Centuries of traditional use (Evidence grade A · Traditional use long-standing)Long-standing traditional staple
Inner-ankle point for menstrual cramps
Why it may be relevant
If you want hands-on relief you can apply yourself, SP6 is the classic self-press point for period pain.
Why try it
Traditionally pressed to ease menstrual cramps, regulate the cycle, and calm PMS-type tension.
Dose or use
Find it about four finger-widths above the inner ankle bone; press firmly 2-3 min per side during cramping.
Time to results
May offer relief within the same session
Key study
Systematic Review & Meta-Analysis of RCTs (2025, PMID 41138782): acupressure trials for primary dysmenorrhea, in which SP6 is the most commonly studied point, found reduced menstrual pain intensity.
Caution
Avoid SP6 during pregnancy, as it is traditionally considered a labor-stimulating point.
Acupressure
Supported by controlled trials· Centuries of traditional use (Evidence grade A · Traditional use long-standing)Long-standing traditional staple
DIY pressure points you can do at home
Why it may be relevant
If you want hands-on relief you can apply yourself during cramping, acupressure is practical and immediate.
Why try it
Traditionally used to stimulate specific points — such as SP6 on the inner ankle — to help ease menstrual pain.
Dose or use
Press firmly 2–3 min, both sides, 1–2x daily during your period.
Time to results
May offer relief within the same session
Key study
Systematic Review & Meta-Analysis of RCTs (2025, PMID 41138782): 'Efficacy and safety of acupressure for primary dysmenorrhea' pooled 23 randomized trials and found acupressure reduced menstrual pain intensity versus control.
Caution
Avoid SP6 and other strong points during pregnancy.
CV4 (Guanyuan) - Conception Vessel 4
Centuries of traditional use· Human evidence not yet assessed (Evidence grade not assigned · Traditional use long-standing)Long-standing traditional staple
Lower-belly point over the uterine area
Why it may be relevant
If you'd rather work directly where the cramping sits, CV4 is a lower-abdomen point you can press yourself.
Why try it
Traditionally pressed to relieve cramps and help settle menstrual pain and irregularity.
Dose or use
Find it about four finger-widths below the navel; press gently but firmly 2-3 min during cramping.
Time to results
May offer relief within the same session
Key study
Traditionally used for menstrual cramps; this specific use has not been confirmed here in controlled clinical trials.
Caution
Avoid firm lower-abdomen pressure during pregnancy; press gently and stop if it feels uncomfortable.

My pain feels deep and inflamed — I want to work on what's driving it

Curcumin
Supported by smaller clinical studies· Centuries of traditional use (Evidence grade B · Traditional use long-standing)Long-standing traditional staple
Turmeric's key anti-inflammatory compound
Why it may be relevant
If your cramps feel inflamed and achy, curcumin's traditionally recognized anti-inflammatory properties make it a relevant fit.
Why try it
Traditionally used to help modulate inflammatory pathways that contribute to prostaglandin-driven menstrual pain.
Dose or use
Follow product labeling; consult a healthcare practitioner.
Time to results
Typically 2–8 weeks
Key study
Randomized Controlled Trial (2025, PMID 41473861): a triple-blind trial found curcumin capsules reduced the severity and duration of primary dysmenorrhea.
Caution
May interact with blood thinners; use cautiously if you have gallbladder issues.
Boswellia
Centuries of traditional use· Limited human trials so far (Evidence grade C · Traditional use long-standing)Long-standing traditional staple
Resin herb traditionally used for inflammation
Why it may be relevant
If your cramping has a deep, inflammatory quality, Boswellia's traditional use targets that type of pain.
Why try it
Traditionally used to inhibit inflammatory enzymes, potentially helping to reduce the intensity of inflammatory menstrual discomfort.
Dose or use
Follow product labeling; consult a healthcare practitioner.
Time to results
Typically 4–8 weeks
Key study
Randomized Controlled Trial (2025, PMID 40642179): a formulation combining Acmella oleracea and Boswellia serrata reduced symptoms and analgesic use in primary dysmenorrhea; Boswellia's individual contribution cannot be isolated from the combination.
Caution
Consult a practitioner if pregnant or on anticoagulant medications.
Magnesium Deficiency
Not yet assessed· We have not reviewed the literature for this one (Evidence grade not assigned · Traditional use recognised)Recognised traditional use
A shortfall linked to muscle cramping
Why it may be relevant
If you're open to addressing a possible root cause, low magnesium is worth checking, since it supports muscle relaxation.
Why try it
Magnesium helps muscles relax; a shortfall is associated with cramps and spasms, so correcting it may ease cramping for some.
Dose or use
Ask a clinician about testing; magnesium is found in leafy greens, nuts, seeds, and whole grains, or taken as a supplement.
Time to results
Typically 1-2 cycles once levels improve
Key study
Low magnesium is associated with muscle cramping; a direct effect on menstrual cramps has not been confirmed here in controlled clinical trials.
Caution
High-dose magnesium supplements can cause loose stools; check with a clinician if you have kidney issues.

When cramps take over, what kind of help feels right for you?

I'd rather take an herb — a warming tea, seed, or plant extract

Fennel
Supported by controlled trials· Centuries of traditional use (Evidence grade A · Traditional use long-standing)Long-standing traditional staple
Aromatic seed herb for cramp relief
Why it may be relevant
If you prefer an internal herbal option, fennel is an antispasmodic seed herb with solid trial support for period pain.
Why try it
Fennel's anethole and related compounds have antispasmodic effects that may relax uterine muscle and ease cramping.
Dose or use
Commonly taken as a fennel extract or tea around the start of your period; follow product labeling.
Time to results
Often within the first day or two of a period
Key study
Systematic Review & Meta-Analysis of RCTs (2020, PMID 33182553): 'Fennel for Reducing Pain in Primary Dysmenorrhea' pooled randomized trials and found fennel reduced menstrual pain intensity.
Caution
May interact with estrogen-sensitive conditions and blood thinners; talk to your doctor if pregnant or on hormone therapy.
Ginger
Supported by controlled trials· Centuries of traditional use (Evidence grade A · Traditional use long-standing)Long-standing traditional staple
Warming root herb used for period pain
Why it may be relevant
If you'd rather take something in, ginger is an easy kitchen-cupboard herb long reached for during cramping.
Why try it
Traditionally taken as tea, capsules, or fresh root to warm the belly and ease the intensity of period cramps.
Dose or use
Follow product labeling; commonly taken as tea or capsules from the start of your period.
Time to results
Often within the first day or two of use
Key study
Systematic Review & Meta-Analysis (2024, PMID 38770631): 'Ginger for Pain Management in Primary Dysmenorrhea' pooled randomized trials and found ginger reduced menstrual pain intensity versus placebo.
Caution
May thin the blood and lower blood sugar; use cautiously if on anticoagulants or diabetes medication.
Fenugreek
Supported by controlled trials· Recognised traditional use (Evidence grade A · Traditional use recognised)Recognised traditional use
Seed herb for menstrual pain relief
Why it may be relevant
If you prefer an internal herbal remedy, fenugreek has a long traditional history of use for easing period cramps.
Why try it
Traditionally used to help relax uterine muscles and reduce the severity of menstrual cramping when taken orally.
Dose or use
Follow product labeling; consult a healthcare practitioner.
Time to results
Typically 1–3 cycles
Key study
Systematic Review & Meta-Analysis (2024, PMID 37594100): 'The Effect of Fenugreek on the Severity of Dysmenorrhea' pooled randomized trials and found fenugreek reduced the severity of menstrual pain.
Caution
Avoid medicinal doses during pregnancy; may lower blood sugar in people on diabetes medications.
Curcumin
Supported by smaller clinical studies· Centuries of traditional use (Evidence grade B · Traditional use long-standing)Long-standing traditional staple
Turmeric's key anti-inflammatory compound
Why it may be relevant
If your cramps feel inflamed and achy, curcumin's traditionally recognized anti-inflammatory properties make it a relevant fit.
Why try it
Traditionally used to help modulate inflammatory pathways that contribute to prostaglandin-driven menstrual pain.
Dose or use
Follow product labeling; consult a healthcare practitioner.
Time to results
Typically 2–8 weeks
Key study
Randomized Controlled Trial (2025, PMID 41473861): a triple-blind trial found curcumin capsules reduced the severity and duration of primary dysmenorrhea.
Caution
May interact with blood thinners; use cautiously if you have gallbladder issues.
Saffron (Crocus sativus)
Supported by smaller clinical studies· Recognised traditional use (Evidence grade B · Traditional use recognised)Recognised traditional use
Spice traditionally used for cycle support
Why it may be relevant
If you prefer taking something internally, saffron is a traditional herbal option historically used for menstrual comfort.
Why try it
Traditionally used to support smooth muscle relaxation and mood during the menstrual cycle.
Dose or use
Follow product labeling; consult a healthcare practitioner.
Time to results
Typically 2–3 cycles
Key study
Systematic Review & Meta-Analysis (2026, PMID 41151539): 'Effect of saffron on premenstrual syndrome and dysmenorrhea' pooled randomized trials and found saffron improved menstrual-cycle symptoms.
Caution
Avoid high doses during pregnancy; may interact with antidepressants.
Boswellia
Centuries of traditional use· Limited human trials so far (Evidence grade C · Traditional use long-standing)Long-standing traditional staple
Resin herb traditionally used for inflammation
Why it may be relevant
If your cramping has a deep, inflammatory quality, Boswellia's traditional use targets that type of pain.
Why try it
Traditionally used to inhibit inflammatory enzymes, potentially helping to reduce the intensity of inflammatory menstrual discomfort.
Dose or use
Follow product labeling; consult a healthcare practitioner.
Time to results
Typically 4–8 weeks
Key study
Randomized Controlled Trial (2025, PMID 40642179): a formulation combining Acmella oleracea and Boswellia serrata reduced symptoms and analgesic use in primary dysmenorrhea; Boswellia's individual contribution cannot be isolated from the combination.
Caution
Consult a practitioner if pregnant or on anticoagulant medications.

I'd see a practitioner — needle-based therapies for cycle pain

Acupuncture
Supported by controlled trials· Centuries of traditional use (Evidence grade A · Traditional use long-standing)Long-standing traditional staple
Needle therapy targeting pain and flow
Why it may be relevant
If you want a practitioner-led, body-based session, acupuncture is a traditional go-to for cycle pain.
Why try it
Traditionally used to regulate qi and blood flow, with the aim of easing uterine cramping and tension.
Dose or use
Work with a qualified, licensed practitioner; ask them how many sessions and how often are right for you.
Time to results
Typically 2–3 cycles
Key study
Systematic Review & Network Meta-Analysis (2026, PMID 41056095): 'Acupuncture-Related Therapies for Primary Dysmenorrhea' pooled randomized trials and found acupuncture-related therapies reduced menstrual pain compared with control.
Caution
Seek a licensed acupuncturist; avoid certain points during pregnancy.
Auricular Acupuncture
Centuries of traditional use· Limited human trials so far (Evidence grade C · Traditional use long-standing)Long-standing traditional staple
Ear-based acupuncture for cycle pain
Why it may be relevant
Another hands-on, practitioner-applied technique that fits if you're open to body-based treatments.
Why try it
Traditionally used to stimulate reflex points on the ear believed to correspond to the uterus and pelvic region.
Dose or use
Work with a qualified, licensed practitioner; ask them how many sessions and how often are right for you.
Time to results
Typically 2–3 cycles
Key study
Systematic Review & Network Meta-Analysis (2026, PMID 41056095): auricular techniques are included among the acupuncture-related therapies studied for primary dysmenorrhea, though ear-specific evidence is more limited and often bundled with body acupuncture.
Caution
Best performed by a trained practitioner; not well-studied in pregnancy.

Keep it simple — a mineral or nutrient my body might be missing

Zinc
Supported by controlled trials· Centuries of traditional use (Evidence grade A · Traditional use long-standing)Long-standing traditional staple
Mineral shown to ease period pain
Why it may be relevant
If you'd rather take something in, zinc is a simple mineral with pooled trial evidence for reducing menstrual pain.
Why try it
Zinc's anti-inflammatory and antioxidant actions may curb the prostaglandins and uterine spasms that drive cramping.
Dose or use
Commonly studied at roughly 30-50 mg daily, often started a few days before your period; follow product labeling and avoid exceeding about 40 mg long-term without guidance.
Time to results
Often within 1-2 cycles
Key study
Systematic Review & Meta-Analysis (2024, PMID 39683510): 'Efficacy of Zinc Supplementation in the Management of Primary Dysmenorrhea' pooled randomized trials and found zinc supplementation reduced menstrual pain severity.
Caution
Doses above about 40 mg/day long-term can deplete copper and upset the stomach; take with food and check with a clinician if you take other medications.
Magnesium Deficiency
Not yet assessed· We have not reviewed the literature for this one (Evidence grade not assigned · Traditional use recognised)Recognised traditional use
A shortfall linked to muscle cramping
Why it may be relevant
If you're open to addressing a possible root cause, low magnesium is worth checking, since it supports muscle relaxation.
Why try it
Magnesium helps muscles relax; a shortfall is associated with cramps and spasms, so correcting it may ease cramping for some.
Dose or use
Ask a clinician about testing; magnesium is found in leafy greens, nuts, seeds, and whole grains, or taken as a supplement.
Time to results
Typically 1-2 cycles once levels improve
Key study
Low magnesium is associated with muscle cramping; a direct effect on menstrual cramps has not been confirmed here in controlled clinical trials.
Caution
High-dose magnesium supplements can cause loose stools; check with a clinician if you have kidney issues.

Something I can do with my own hands — heat or pressure where it hurts

Warm Compress
Supported by controlled trials· Centuries of traditional use (Evidence grade A · Traditional use long-standing)Long-standing traditional staple
Applied heat to soothe cramping muscles
Why it may be relevant
If you want something hands-on you can feel working right away, warmth on the lower belly is about as immediate as it gets.
Why try it
Traditionally used to relax the uterine muscles and ease cramping by bringing warmth and blood flow to the area.
Dose or use
Apply a warm pack or hot water bottle to your lower abdomen for 15-20 minutes as needed.
Time to results
Often eases discomfort within minutes
Key study
Systematic Review & Meta-Analysis (2025, PMID 41657584): 'Heat therapy for primary dysmenorrhea' found applied heat reduced menstrual pain intensity, in some trials comparably to NSAIDs.
Caution
Use a cloth barrier to avoid burns; don't apply heat to broken or numb skin.
SP6 (Sanyinjiao) - Spleen 6
Supported by controlled trials· Centuries of traditional use (Evidence grade A · Traditional use long-standing)Long-standing traditional staple
Inner-ankle point for menstrual cramps
Why it may be relevant
If you want hands-on relief you can apply yourself, SP6 is the classic self-press point for period pain.
Why try it
Traditionally pressed to ease menstrual cramps, regulate the cycle, and calm PMS-type tension.
Dose or use
Find it about four finger-widths above the inner ankle bone; press firmly 2-3 min per side during cramping.
Time to results
May offer relief within the same session
Key study
Systematic Review & Meta-Analysis of RCTs (2025, PMID 41138782): acupressure trials for primary dysmenorrhea, in which SP6 is the most commonly studied point, found reduced menstrual pain intensity.
Caution
Avoid SP6 during pregnancy, as it is traditionally considered a labor-stimulating point.
Acupressure
Supported by controlled trials· Centuries of traditional use (Evidence grade A · Traditional use long-standing)Long-standing traditional staple
DIY pressure points you can do at home
Why it may be relevant
If you want hands-on relief you can apply yourself during cramping, acupressure is practical and immediate.
Why try it
Traditionally used to stimulate specific points — such as SP6 on the inner ankle — to help ease menstrual pain.
Dose or use
Press firmly 2–3 min, both sides, 1–2x daily during your period.
Time to results
May offer relief within the same session
Key study
Systematic Review & Meta-Analysis of RCTs (2025, PMID 41138782): 'Efficacy and safety of acupressure for primary dysmenorrhea' pooled 23 randomized trials and found acupressure reduced menstrual pain intensity versus control.
Caution
Avoid SP6 and other strong points during pregnancy.
CV4 (Guanyuan) - Conception Vessel 4
Centuries of traditional use· Human evidence not yet assessed (Evidence grade not assigned · Traditional use long-standing)Long-standing traditional staple
Lower-belly point over the uterine area
Why it may be relevant
If you'd rather work directly where the cramping sits, CV4 is a lower-abdomen point you can press yourself.
Why try it
Traditionally pressed to relieve cramps and help settle menstrual pain and irregularity.
Dose or use
Find it about four finger-widths below the navel; press gently but firmly 2-3 min during cramping.
Time to results
May offer relief within the same session
Key study
Traditionally used for menstrual cramps; this specific use has not been confirmed here in controlled clinical trials.
Caution
Avoid firm lower-abdomen pressure during pregnancy; press gently and stop if it feels uncomfortable.

Evidence grades describe the strength of published research for Menstrual Cramps (Dysmenorrhea), not a promise of results. Nothing here is medical advice — talk to your clinician before starting anything, especially alongside prescription medication.

How to read the grades below

What are you hoping to get out of this — relief today, or an easier cycle next month?

I want to get ahead of it — make my next few cycles less painful

I'm cramping right now — I need something that works today

SP6 (Sanyinjiao) - Spleen 6

CV4 (Guanyuan) - Conception Vessel 4

My pain feels deep and inflamed — I want to work on what's driving it

Magnesium Deficiency