Answer

Is intermittent fasting safe for women?

Intermittent Fasting fasting womens-health hormones

By Arun AgrahriLast reviewed 4 timecoded sources

Short answer

The counted sources lean toward yes for a gentle daily window of about 12 hours, and most of them attach limits. Twelve hours is the figure named most, and some advice runs to 12 to 14. They urge more care with longer fasts, pregnancy and nursing. Precis has not read any studies on it yet.

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women who fast or are thinking of starting.
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Based on what researchers say in public interviews on YouTube. Educational only, not medical advice. Ask a qualified clinician before changing a supplement, medication, treatment, or testing plan.
Strong consensus for

Fasting is worth doing for health.

The verdict on Intermittent Fasting overall. 35 sources: 24 positive, 11 partly

What the evidence says

positive partly neutral negative Each researcher and each study counts once per claim, however often they come up.

  1. Leaning for

    Gentle intermittent fasting with a 12 to 14 hour daily window is safe for women.

    15 sources: 6 positive, 9 partly.

    Researchers say

    1 positive, 9 partly

    Studies show

    5 positive

    5 papers we read

    29 more not counted · see why
    We could not tell what position it takes on this claim. 17
    We could not confirm who is speaking. 9
    We could not tell where the evidence comes from. 2
    A host's remark inside an interview. 1
    Show the receipts from 15 sources

    1. Dr. Jason Fung Video · positive · 2 mentions

      on Rangan Chatterjee's channel, at 1:13:31 · positive · Opinion

      “I think that's that's probably a good place to start off with that's going to be safe for everybody.”

      on Rangan Chatterjee's channel, at 1:31:10 · positive · Opinion

      “The women can fast. Like there's nothing inherently dangerous about fasting in women.”

    2. Controlled trial, Nutr Diabetes, 2021, PMID 33446635 Study · positive

      There were no reports of adverse events or other safety or tolerability findings.

    3. Other primary study, Breast Cancer Res Treat, 2022, PMID 35441995 Study · positive

      POF is feasible among patients with a history of breast cancer and may potentially improve BMI, mood, and fatigue without detrimental effects on overall QOL.

    4. Other primary study, J Clin Transl Sci, 2024, PMID 39790469 Study · positive

      No adverse events or effects related to the intervention were reported from either the PNF or HED groups.

    5. Other primary study, J Clin Transl Sci, 2024, PMID 39830610 Study · positive

      Throughout the 8-week intervention, no adverse events or effects related to the intervention were reported.

    6. Other primary study, Breast Cancer Res Treat, 2025, PMID 40794365 Study · positive

      The fasting intervention was well tolerated, with 74.1% of women meeting the fasting goal.

    7. Rangan Chatterjee, on Rangan Chatterjee's channel, at 1:06:46 Video · partly · Opinion

      “I would say 12 hours works for pretty much everyone”

    8. Doctor Tim Spector, on The Diary Of A CEO, at 37:39 Video · partly · Opinion

      “is right for some people but importantly it's not right for everybody”

    9. Mindy Pelz Video · partly · 5 mentions

      on Rangan Chatterjee's channel, at 33:33 · partly · Opinion

      “if you can get to that first fasting ledge of 15 hours for that 40-year-old woman that is gold except the week before your parot”

      on Rangan Chatterjee's channel, at 2:10:30 · partly · Opinion

      “women that are nursing I recommend that you keep your fast under 15 hours”

      on Rangan Chatterjee's channel, at 2:08:59 · partly · Opinion

      “if you can get to that first fasting ledge of 15 hours for that 40-year-old woman that is gold except the week before your parot”

      on Rangan Chatterjee's channel, at 1:09:03 · partly · Opinion

      “if your toxic load is high, you're not going to want to do more than like a 15, 16-hour fast during manifestation phase”

      on Rangan Chatterjee's channel, at 14:34 · partly · Opinion

      “And then women that are nursing, I recommend that you keep your fast under 15 hours”

    10. Dr. Satchin Panda, on FoundMyFitness, at 1:08:06 Video · partly · Opinion

      “anyone from 5-year-old to 100-year-old year old can do 12 hours' time-restricted eating without much concern about adverse side effects”

    11. Andrew Huberman, on Huberman Lab, at 3:09:47 Video · partly · Opinion

      “and you are following intermittent fasting, time-restricted feeding, well, then chances are pretty good that it's not disrupting your fertility and likelihood of fertilization”

    12. Dr. Dale Bredesen, on FoundMyFitness, at 31:26 Video · partly · Opinion

      “If you're ApoE4 negative, 12 to 14 hours. And be careful, if you have a very low BMI, you can lose weight”

    13. Mark Hyman, on The Dr. Hyman Show, at 30:34 Video · partly · Opinion

      “anybody can go 12 hours and i think we should and it's probably good for the baby”

    14. Dr. Pradip Jamnadas, on Rangan Chatterjee's channel, at 50:33 Video · partly · Opinion

      “that's probably a good place to start off with that's going to be safe for everybody”

    15. Cynthia Thurlow Video · partly · 2 mentions

      on The Dr. Hyman Show, at 17:24 · partly · Opinion

      “I encourage women to do a little less fasting kind of back off the gas maybe they're doing 12 or 13 hours of digestive rest”

      on The Dr. Hyman Show, at 05:58 · partly · Opinion

      “if you are a lean 32 year old female I'm going to talk to you about 12 hours of digestive rest”

Where the sources disagree

Leaning for

Gentle intermittent fasting with a 12 to 14 hour daily window is safe for women.

Supports it 6 sources

Researchers

Studies

Partly 9 sources

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Detailed Answer

The claim is that gentle intermittent fasting, with a daily window of 12 to 14 hours without food, is safe for women. The counted mentions all come from tape, and nearly all of them back the claim in part: they agree on a short overnight fast and add a condition. Precis has not read any studies on it yet, so no trial result sits behind the verdict.

Twelve hours as the floor

Satchin Panda, a guest on Rhonda Patrick's show, says anyone from 5 to 100 years old can do 12 hours of time-restricted eating without much concern about side effects. Rangan Chatterjee, on his own show, says 12 hours works for nearly everyone. Jason Fung, a guest on Chatterjee's show, says there is nothing inherently dangerous about fasting in women, though women probably respond differently.

Answering a listener on his own show, Mark Hyman says anybody can go 12 hours.

Where the limits start

Cynthia Thurlow, a guest on Hyman's show, encourages women to back off to 12 or 13 hours in the second half of the cycle, after ovulation. Tim Spector, a guest on The Diary of a CEO, says fasting is right for some people but not for everybody. Dale Bredesen, a guest on Patrick's show, suggests 12 to 14 hours for people without the ApoE4 gene variant, and warns that people with a very low BMI can lose weight.

Mindy Pelz, a guest on Chatterjee's show, says 15 hours is a good target for a 40-year-old woman, except in the week before her period. She tells nursing women to keep their fast under 15 hours and says fasting is not a tool for pregnant women. Anyone with an eating disorder, she says, should involve their doctor or not fast.

Fasting and training

Stacy Sims is a guest on Andrew Huberman's show. She says holding a fast until noon, or eating very little on some days, is very detrimental for active women, unless they have PCOS. Fasted workouts, she says, raise stress and cortisol. Her remark is not counted toward this claim.

Related Questions

What fasting window do the counted sources name for women?
Twelve hours comes up most. Thurlow suggests women back off to 12 or 13 hours after ovulation, and Pelz gives 15 hours for a 40-year-old woman outside the week before her period.
Is fasting safe while pregnant or nursing?
Pelz says fasting is not a tool for pregnant women and that nursing women should keep fasts under 15 hours. Hyman would not recommend fasts of a day or more in pregnancy.
Should active women train fasted?
Sims, in a remark that is not counted, says fasted workouts raise stress and cortisol in women. She calls fasting until noon very detrimental for active women.

More Questions About Intermittent Fasting

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