Can You Take Sleep Supplements With Antidepressants?

It depends on the ingredient, and the person who answers for your own prescription is your pharmacist or GP. Tryptophan and 5-HTP act on serotonin, as SSRIs, SNRIs and MAOIs do, and are the ingredients to hold back without that conversation; ashwagandha, valerian, chamomile, lemon balm and theanine mainly add drowsiness, which matters most with a sedating antidepressant such as mirtazapine or amitriptyline; magnesium has no documented interaction with any antidepressant; and melatonin is a prescription-only medicine in the UK. Every NHS page for these medicines carries the same instruction, in the citalopram wording: "tell your doctor if you're taking any other medicines, herbal remedies, vitamins or supplements".¹ Each ingredient follows, under the Wellgard sleep guide.

Sources checked on 30 October 2026.

Why is this question so hard to get answered?

Because the two halves are regulated apart. A medicine's interactions are studied before licensing; herbal remedies and supplements, in the NHS's words, are "generally not tested for the effect they have on other medicines".⁷ The NHS pages for all seven antidepressants name one supplement to avoid, St John's wort, and otherwise hand the question to the prescriber.^{1, 2, 3, 4, 5, 6, 7}

Which sleep-supplement ingredients act on serotonin?

Tryptophan and 5-HTP, directly; ashwagandha, measurably but by a different route. The NHS describes serotonin syndrome as "a rare but serious condition that causes a fast heartbeat, sweating, shaking, twitching muscles and feeling confused or agitated".⁸ A 2023 review adds that it can follow one serotonergic drug or "a drug interaction between two or more serotonergic drugs".⁹

Tryptophan is the amino acid the body converts into serotonin. Five case reports describe a toxic reaction after fluoxetine was combined with L-tryptophan, and a review of tryptophan alongside antidepressants concluded that "the risk of the serotonin syndrome is small, but it can occur".^{10, 11} The one controlled trial to pair them gave 30 adults with major depression 20 mg of fluoxetine a day with 2 to 4 g of tryptophan or placebo for eight weeks; it recorded no serotonin syndrome, and daytime drowsiness at 4 g a day.¹² In the UK, L-tryptophan may be added to a food supplement only if "the recommended daily dose for that food supplement does not exceed 220 mg", while pooled sleep trials found less time awake in the night, more so at 1 g or more a day.^{13, 14} Does tryptophan help you sleep? has the detail.

5-HTP is one step further along the same pathway, and the 220 mg tryptophan limit does not cover it.¹³ A review of 5-HTP singles out eosinophilia myalgia syndrome and serotonin syndrome among its safety issues.¹⁵

Ashwagandha raised circulating serotonin by a mean of 31.75 ng/mL across 23 placebo-controlled trials in 1,706 adults, with heterogeneity flagged by the authors.¹⁶ Two six-week trials from one Iranian research group gave it alongside SSRIs, to 40 people with generalised anxiety disorder and 30 with obsessive-compulsive disorder, with no adverse effects reported;^{24, 25} small trials are not an interaction study. Who should not take ashwagandha? has the liver and thyroid cautions.

Which ingredients add drowsiness to a sedating antidepressant?

Most of the herbal ones, in theory, and it matters most for mirtazapine and amitriptyline. The NHS lists "feeling drowsy or sleepy" among mirtazapine's common side effects and names benzodiazepines among the medicines that "may not mix well" with it.⁶ For amitriptyline: "There's not enough information to say that other complementary medicines and herbal remedies are safe to take with amitriptyline".⁷

Valerian is the clearest case: the NHS insomnia page says pharmacy sleep aids containing "valerian or lavender" "may help you sleep better for 1 to 2 weeks", and "should not be taken for any longer".¹⁷ Chamomile and lemon balm have no interaction study either; the caution is added drowsiness. Ashwagandha: across 23 trials of root extract in 2,317 healthy adults, "transient drowsiness" was among the mild events, infrequent and reported in both groups.¹⁸ Theanine has no interaction study with any antidepressant either; the NHS answer for remedies not tested with a medicine is to tell the doctor or pharmacist,⁷ which is where what L-theanine does leaves it too.

Is magnesium a problem with antidepressants?

Not on the record: nothing published reports an interaction between a magnesium supplement and an antidepressant; the one record pairing the words concerns a magnesium salt of an epilepsy medicine taken with venlafaxine, a medicine interaction.¹⁹ Magnesium does not act on serotonin reuptake and none of the seven NHS pages names it. Its documented interactions are with tetracycline and quinolone antibiotics and bisphosphonates, whose absorption it reduces, so doses are spaced apart;²⁶ what not to take with magnesium gives the spacing.

Do antidepressants themselves change sleep?

Yes, in both directions. "Problems sleeping" is a listed common side effect of citalopram and sertraline, with "dizziness or drowsiness" alongside on the sertraline page; mirtazapine sits at the other end.^{6, 8, 20} None of this is a reason to change or stop an antidepressant on your own; it is a reason to tell the prescriber that sleep is the problem. When to see a GP about sleep lists the signs that should not wait.

What should you ask before trying anything?

Take the ingredient list and ask three things: does anything here act on serotonin (tryptophan, 5-HTP, St John's wort, ashwagandha)? Does anything add to drowsiness with my medicine (valerian, chamomile, lemon balm, ashwagandha, theanine)? If I notice anything, what do I stop and who do I call? If serotonin syndrome symptoms appear, call 111 if you "think you might be having serious side effects",⁸ and 999 for a swollen throat or tongue or difficulty breathing.^{8, 20} Report suspected side effects of a medicine, including a THR-registered herbal medicine, to the Yellow Card scheme;²¹ a reaction to a food supplement goes elsewhere: report it to your local authority's food safety team, which works with the Food Standards Agency.²⁷ Collagen with antidepressants applies the same framework.

What we don't know

No trial has paired theanine, chamomile, lemon balm or valerian with an antidepressant, so added drowsiness is untested. The two ashwagandha trials alongside SSRIs ran six weeks in 70 people and could not detect rare interactions.^{24, 25} Whether 220 mg of tryptophan adds to an SSRI's serotonin load is unstudied: the only controlled trial used 2 to 4 g.^{12, 13} How often serotonin syndrome occurs is unknown.⁹

Frequently asked questions

Can I take 5-HTP with sertraline?

Not without your pharmacist or prescriber agreeing. Both act on serotonin, the NHS lists serotonin syndrome among sertraline's serious side effects, and the 5-HTP review singles out serotonin syndrome.^{15, 20}

Can I take magnesium glycinate with paroxetine or sertraline?

No interaction between any magnesium supplement and any antidepressant has been documented, and magnesium does not act on serotonin.¹⁹ Tell your pharmacist, as the NHS asks for every supplement.¹

Is there a sleep aid I can take with sertraline?

No trial we found has tested one with sertraline, so ask the pharmacist, who can see your full list; the NHS's own answer for pharmacy sleep aids is 1 to 2 weeks at most and "Check with your doctor before taking anything for your sleep problems".¹⁷

Sources

1. NHS. Citalopram: other medicines. Reviewed 26 June 2026. nhs.uk.
2. NHS. Sertraline: other medicines. Reviewed 8 September 2025. nhs.uk.
3. NHS. Fluoxetine: other medicines. Reviewed 1 June 2026. nhs.uk.
4. NHS. Escitalopram: other medicines. Reviewed 18 June 2026. nhs.uk.
5. NHS. Venlafaxine: other medicines. Reviewed 6 July 2026. nhs.uk.
6. NHS. Mirtazapine: other medicines and herbal supplements; side effects. Reviewed 18 August 2026. nhs.uk.
7. NHS. Amitriptyline for depression: other medicines. Reviewed 28 February 2025. nhs.uk.
8. NHS. Citalopram: about citalopram; side effects. Reviewed 26 June 2026. nhs.uk.
9. Mikkelsen N, et al. Serotonin syndrome: a focused review. Basic & Clinical Pharmacology & Toxicology, 2023. Narrative review; funding not stated. PubMed 37309284.
10. Steiner W, Fontaine R. Toxic reaction following the combined administration of fluoxetine and L-tryptophan. Biological Psychiatry, 1986. Case series, 5 patients; funding not stated. PubMed 3488767.
11. Young SN. Use of tryptophan in combination with other antidepressant treatments. Journal of Psychiatry and Neuroscience, 1991. Narrative review; funding not stated. PubMed 1797098.
12. Levitan RD, et al. Tryptophan combined with fluoxetine in major depressive disorder. Journal of Psychiatry and Neuroscience, 2000. Randomised placebo-controlled trial, 30 adults, 8 weeks; funding not stated. PubMed 11022398.
13. The Tryptophan in Food (England) Regulations 2005, SI 2005/2630, regulation 5. legislation.gov.uk.
14. Sutanto CN, et al. The impact of tryptophan supplementation on sleep quality. Nutrition Reviews, 2022. Systematic review of 18 articles, 4 pooled; funding not stated. PubMed 33942088.
15. Turner EH, et al. Serotonin a la carte: supplementation with 5-hydroxytryptophan. Pharmacology & Therapeutics, 2006. Narrative review; funding not stated. PubMed 16023217.
16. Fornalik M, et al. Hormonal modulation with Withania somnifera. Planta Medica, 2026. Meta-analysis of 23 randomised trials, 1,706 adults; no conflicts declared. PubMed 41740946.
17. NHS. Insomnia. Reviewed 19 March 2024. nhs.uk.
18. Coope OC, et al. Safety and tolerability of standardised ashwagandha root extract in healthy adults. Pharmaceuticals, 2026. Systematic review of 23 trials, 2,317 healthy adults; no external funding, two authors declare supplement-industry consulting or employment. PubMed 42198398.
19. Zhan Z, et al. Serotonin syndrome induced by a single dose of venlafaxine and magnesium valproate. Psychiatria Danubina, 2021. Case report, 1 patient; funding not stated. PubMed 34185746.
20. NHS. Side effects of sertraline. Reviewed 8 September 2025. nhs.uk.
21. GOV.UK. Report a problem with a medicine or medical device (Yellow Card scheme). gov.uk.
22. NHS. Taking melatonin with other medicines and herbal supplements. Reviewed 13 February 2023 (review overdue). nhs.uk.
23. NHS. About melatonin. Reviewed 13 February 2023 (review overdue). nhs.uk.
24. Jahanbakhsh SP, et al. Complementary Therapies in Medicine, 2016. Randomised placebo-controlled trial, 30 adults with obsessive-compulsive disorder on SSRIs, 6 weeks; funded by a university (publisher's funder record). PubMed 27515872.
25. Fuladi S, et al. Current Reviews in Clinical and Experimental Pharmacology, 2021. Randomised placebo-controlled trial, 40 adults with generalised anxiety disorder on SSRIs, 6 weeks; funder not stated in the abstract. PubMed 32282308.
26. Doxycycline and ciprofloxacin SmPCs, section 4.5, revised 17 March and 7 October 2026: doxycycline, ciprofloxacin; NHS alendronic acid, reviewed 7 May 2025, nhs.uk.
27. Food Standards Agency. How to report a food safety or hygiene issue for members of the public. Updated 5 August 2026. gov.uk.

Spotted something out of date? Email support@wellgard.co.uk with the page address and the sentence.

Show your pharmacist or GP the full ingredient list before starting any sleep supplement, and never stop or change your medicine without speaking to them first.