Can You Take Collagen With Antidepressants?

Yes, as far as the published evidence goes: no interaction between collagen peptides and any antidepressant has been documented in a trial or a case report, and a PubMed search in October 2026 finds none for citalopram, sertraline, fluoxetine, escitalopram, venlafaxine, mirtazapine or amitriptyline. Collagen is a food protein, and none of the NHS pages for these medicines names protein or collagen as something to avoid. "No documented interaction" is not the same as a formal interaction study, and none has been run; and the NHS gives the same instruction for every antidepressant: "tell your doctor if you're taking any other medicines, herbal remedies, vitamins or supplements".^{1, 2} So the person who confirms this for your own prescription is your pharmacist or GP, and the collagen label is what to show them.

Is there a known interaction between collagen and antidepressants?

No documented one. The published literature contains no case report or trial of an interaction between collagen peptides and any medicine, antidepressants included. Online interaction lists for collagen come from blends, where a herb or vitamin is the culprit, and the side-effects page separates the two. For citalopram: "There are some medicines, remedies and supplements that may not mix well with citalopram", the one supplement it names is St John's wort ("Do not use the herbal supplement St John's wort when taking citalopram"), and on food, "You can eat as normal while taking citalopram".^{1, 3} The sertraline, fluoxetine, escitalopram, venlafaxine and mirtazapine pages carry the same three sentences for their own medicine, with grapefruit juice the one food named on the sertraline page.^{2, 4, 5, 6, 17} No NHS antidepressant page tells readers to limit protein, and collagen is protein.

Where does the serotonin worry come from?

From a real body of research, read backwards. Tryptophan is an essential amino acid and the raw material the brain uses to make serotonin, and collagen is the one common protein that contains none of it.⁷ Researchers use that gap deliberately: acute tryptophan depletion lowers brain serotonin for a few hours so its role in mood and memory can be studied, and a Dutch group developed a gelatine-based collagen drink, low in tryptophan, that is cheaper than the traditional amino-acid mixture.^{8, 9} In 15 healthy volunteers it cut plasma tryptophan by 74% and its ratio to the other large amino acids by 82% within three to four hours.⁸ A 2013 review concluded that low serotonin after tryptophan depletion "lowers mood in some people".¹⁰ The online conclusion follows from there: collagen is tryptophan-free, so it must lower serotonin.

The comparison fails on what the drink is for. A depletion drink is designed to be tryptophan-free and is given on its own, in a laboratory, as a single large load (the standard formulations are a 50 g dose), so that no other protein arrives to supply the missing amino acid.^{8, 11} A serving of collagen beside a normal day's meals is the opposite arrangement: the tryptophan it lacks comes in with the eggs, dairy, meat, fish, pulses and grains eaten around it. Modelling of a typical Western diet found that collagen peptides can supply up to 36% of a day's protein while every indispensable amino acid requirement, tryptophan included, is still met, and the 2.5 to 15 g a day used in the collagen trials sits well under that ceiling.⁷ A methods review found gelatine "only partially effective" even as a laboratory depletion agent, and in the one evaluation that measured mood alongside a gelatine-based collagen drink, 29 healthy volunteers who took the tryptophan-free version showed the expected fall in plasma tryptophan but no significant difference in mood, side effects, cortisol, blood pressure or heart rate from the version with tryptophan added back.^{11, 12}

Does collagen affect how citalopram or sertraline work?

Nothing has been measured, and nothing is expected from a protein food. The NHS describes citalopram as a selective serotonin reuptake inhibitor, "thought to work by increasing the level of serotonin (a chemical in the brain linked to mood)".³ None of these medicines carries an empty-stomach rule: the NHS says citalopram can be taken "with or without food", so there is no timing gap to organise, unlike collagen with thyroid medication, where levothyroxine's food rule is the whole question.³

The ingredients that do need checking are the ones some collagen products add. St John's wort appears in a few "mood" blends, and every NHS page above says not to use it with the medicine. Biotin, common in hair-and-nails blends, interfered with 9 of 23 biotin-based laboratory assays, thyroid tests among them, after a week of a supplement-level dose in six healthy adults, so mention a biotin blend before any blood test.¹³ What vitamins to take with collagen covers the additions worth having.

Does collagen help with anxiety or low mood?

No trial has tested collagen peptides for mood or anxiety in people, so there is nothing to report either way. The one controlled setting in which mood was measured alongside a collagen drink was the depletion work above, where the tryptophan-free and tryptophan-added versions did not differ.¹² What collagen trials have measured is skin hydration and elasticity, joint comfort, bone density and nail growth, and the Wellgard collagen guide sets those results out trial by trial. If low mood or anxiety is the reason you are searching, that conversation belongs with your GP rather than with a supplement.

What should I tell my pharmacist before adding collagen?

Three things: which antidepressant you take; the full ingredient list of the product, one line for a plain powder and perhaps a dozen for a blend; and how much you plan to take; how much collagen to take a day gives the trial ranges. The NHS amitriptyline page states the general rule: "Always check with your doctor or a pharmacist before starting any new medicine while you're taking amitriptyline", and, of herbal remedies, that "They're generally not tested for the effect they have on other medicines".¹⁴

When should I speak to a GP, or call 111 or 999?

The NHS lists each medicine's serious side effects. For citalopram and sertraline the list includes serotonin syndrome, "a rare but serious condition that causes a fast heartbeat, sweating, shaking, twitching muscles and feeling confused or agitated", and the instruction is to call NHS 111 if "you're taking citalopram and think you might be having serious side effects" or "you're having thoughts about harming yourself".^{15, 16} For a serious allergic reaction, "a swollen throat or tongue" or "a raised, itchy rash and difficulty breathing", the sertraline page says to call 999.¹⁶ Collagen has not been linked to any of these; the response is the same regardless of cause. Do not stop or change an antidepressant on the strength of a supplement worry; that is a decision for you and your GP.

Frequently asked questions

Can I take collagen with citalopram?

No interaction between collagen peptides and citalopram has been documented, the NHS says citalopram can be taken "with or without food", and collagen is food. Tell your pharmacist or GP you are taking it, as the NHS asks for every supplement.^{1, 3}

Can I take collagen with mirtazapine or amitriptyline?

The same answer: none documented. The NHS mirtazapine page says "You can eat and drink normally when taking mirtazapine", and the amitriptyline page asks you to check with your doctor or a pharmacist before starting anything new.^{6, 14}

Does collagen lower serotonin?

Not at a serving beside meals, as far as anything has been measured: the research drinks are tryptophan-free loads taken alone in a laboratory, and collagen can make up about a third of a day's protein while the diet still meets the tryptophan requirement.^{7, 8, 11}

What should you not mix with collagen?

Nothing on collagen's own account. The ingredients to check are in blends: St John's wort, which the NHS says not to use with any of these antidepressants; biotin before a blood test; and herbal extracts, which the NHS says are "generally not tested for the effect they have on other medicines".^{1, 13, 14}

Can collagen cause low mood?

No trial or case report says so. In the one controlled study that measured mood with a tryptophan-free collagen drink, 29 volunteers showed no difference from the tryptophan-added version.¹²

Sources

1. NHS. Citalopram: taking it with other medicines and herbal supplements. nhs.uk.
2. NHS. Sertraline: taking it with other medicines and herbal supplements. nhs.uk.
3. NHS. Citalopram: about citalopram; how and when to take it. nhs.uk.
4. NHS. Escitalopram: taking it with other medicines and herbal supplements. nhs.uk.
5. NHS. Venlafaxine: taking it with other medicines and herbal supplements. nhs.uk.
6. NHS. Mirtazapine: taking it with other medicines and herbal supplements; food, drink and alcohol. nhs.uk.
7. Paul C, Leser S, Oesser S. Significant amounts of functional collagen peptides can be incorporated in the diet while maintaining indispensable amino acid balance. Nutrients, 2019. PubMed 31096622.
8. Evers EA, et al. Effects of a novel method of acute tryptophan depletion on plasma tryptophan and cognitive performance in healthy volunteers. Psychopharmacology, 2005. PubMed 15702361.
9. Sambeth A, et al. Memory impairments in humans after acute tryptophan depletion using a novel gelatin-based protein drink. Journal of Psychopharmacology, 2009. PubMed 18515454.
10. Young SN. Acute tryptophan depletion in humans: a review of theoretical, practical and ethical aspects. Journal of Psychiatry and Neuroscience, 2013. PubMed 23428157.
11. Badawy AA, Dougherty DM. Standardization of formulations for the acute amino acid depletion and loading tests. Journal of Psychopharmacology, 2015. PubMed 25586395.
12. Stenbæk DS, et al. Evaluation of acute tryptophan depletion and sham depletion with a gelatin-based collagen peptide protein mixture. European Neuropsychopharmacology, 2016. PubMed 26655163.
13. Li D, et al. Association of biotin ingestion with performance of hormone and nonhormone assays in healthy adults. JAMA, 2017. PubMed 28973622.
14. NHS. Taking amitriptyline for depression with other medicines and herbal supplements. nhs.uk.
15. NHS. Citalopram: side effects. nhs.uk.
16. NHS. Sertraline: side effects. nhs.uk.
17. NHS. Fluoxetine: taking it with other medicines and herbal supplements. nhs.uk.

This article is general information, not medical advice. If you take an antidepressant, tell your pharmacist or GP about every supplement you take, including collagen, and never stop or change your medicine without speaking to them first.