The Kasivit Journal — Issue 1

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Issue 1 · May 12, 2026

GLP-1 Nutrition, Gut Permeability & Magnesium vs. Melatonin: What the Evidence Shows

By the Kasivit Editorial Team · 8 min read

Editorial Note

Welcome to Issue 1 of The Kasivit Journal.

We started The Kasivit Journal because what clinical research shows and what people often hear about supplements can differ a great deal. Too much supplement advice is vague, overstated, or untethered from evidence. Every issue, we aim to close that gap, clearly and honestly. Kasivit sells supplements, so weigh our views accordingly and check the sources listed at the end of this issue.

Expert groups describe GLP-1 medications such as semaglutide (Ozempic, Wegovy) as having transformed the management of obesity.1 They also reduce appetite, and eating much less can lead to nutritional gaps; expert groups note that clinician and public knowledge of the nutritional side of treatment is limited.2 GLP-1 medications are also associated with a higher risk of gallbladder and bile duct problems;3 seek prompt medical care for severe upper-abdominal pain, fever or yellowing of the skin. This issue is largely about nutrition during GLP-1 treatment. Nothing in it is a reason to start, stop or change a prescribed medicine; ask your prescriber or pharmacist.

— The Kasivit Editorial Team

From the Kasivit Blog
May 9, 2026 · Gut Health · GLP-1
L-Glutamine and Leaky Gut: What the Evidence Actually Says

The gut lining is a single cell layer thick. In one trial in adults with post-infectious, diarrhea-predominant irritable bowel syndrome and increased gut permeability, glutamine improved symptoms and normalised permeability compared with placebo.4 We did not find trials in people taking GLP-1 medications. Glutamine is not suitable for everyone; the full article lists cautions.

Read the full article →
May 7, 2026 · Sleep Science · Magnesium
Magnesium and Melatonin for Sleep: What the Evidence Shows

Melatonin and magnesium have both been studied for sleep. In a meta-analysis of 19 trials in people with primary sleep disorders, melatonin shortened the time to fall asleep by about 7 minutes and lengthened total sleep time by about 8 minutes.5 For magnesium, a review found only three small trials in older adults with insomnia, and the evidence was low to very low quality.6 Neither is a substitute for medical care if sleep problems continue.

Read the full article →
May 5, 2026 · GLP-1 · Ozempic
Supplements and Ozempic (Semaglutide): What the Evidence Shows

GLP-1 medications reduce appetite, and eating much less can lead to nutritional gaps.2 This article looks at five supplements people ask about on GLP-1 therapy and how strong the evidence is for each. Expert groups note that direct evidence on supplements in people taking these medicines is limited.1

Read the full article →
Evidence Corner
1. Berberine lowers blood glucose modestly, but has not been studied alongside GLP-1 medications
J Nutr, 2023 · Meta-analysis, 20 RCTs7

Across 20 randomized trials (1,761 people), berberine lowered fasting glucose by about 0.5 mmol/L and HbA1c by about 4.5 mmol/mol compared with placebo.7 We did not find any trial of berberine combined with a GLP-1 medication. A 2026 review lists additive blood-glucose lowering (hypoglycemia) among berberine's possible drug interactions, along with effects on liver enzymes (CYP3A4, CYP2D6, CYP2C9) and drug transporters,8 so it could add to the effect of GLP-1 medications or other diabetes medicines. Berberine can also cause stomach upset: across trials, gastrointestinal side effects were reported in 2-23% of berberine groups versus 2-15% of placebo groups.9 A 2026 toxicology review lists pregnancy status among the factors that modulate berberine toxicity.10

Takeaway: ask your prescriber or pharmacist before adding berberine to a GLP-1 medication, to a diabetes medicine or to any medicine you take regularly. Ask a clinician before use if you are pregnant, planning pregnancy or breastfeeding.
2. Gut bacteria composition changed after 12 weeks of semaglutide in a small study
Diabetes Metab Syndr Obes, 2025 · 15 adults with type 2 diabetes11

In a small study of 15 adults with type 2 diabetes poorly controlled by metformin, gut bacteria composition changed between samples taken before and after 12 weeks of semaglutide. The study had no probiotic group, so it cannot say whether probiotics change these effects.11 We did not find trials showing that probiotics prevent these changes or reduce the side effects of GLP-1 medications.

Takeaway: the evidence does not support a particular probiotic dose or start time for people taking GLP-1 medications. Probiotics are generally considered safe for most people, but risks including systemic infection have been described in susceptible individuals,12 and long-term safety in at-risk groups cannot be concluded from the available trials.13 Ask your clinician first if you are immunocompromised or seriously ill.
Product Spotlight
Kasivit Magnesium Glycinate Capsules
275 mg elemental Mg · 3 capsules · 30 servings

Magnesium is a cofactor in hundreds of enzymatic reactions.14 About half of Americans (48%) consumed less than the required amount of magnesium from food in 2005–2006,15 and eating much less on GLP-1 therapy may widen that gap. That figure describes low intake, not measured deficiency. Magnesium oxide was poorly absorbed (fractional absorption about 4%) in one study of normal volunteers, while magnesium chloride, lactate and aspartate were absorbed better;16 glycinate was not tested in that study, and we did not find trials showing that it is better absorbed or better tolerated than other forms.

One serving (3 capsules) provides 275 mg of elemental magnesium, per the label. The US upper limit for supplemental magnesium in adults is 350 mg/day; it was set because of diarrhea, and some researchers argue it should be re-evaluated.17 Take it as directed on the product label, and count any other magnesium supplements you use. Magnesium supplements are not suitable for everyone: data on magnesium in chronic kidney disease are limited and doses vary widely between studies,18 so ask a clinician before taking magnesium if you have kidney disease, and ask your prescriber or pharmacist whether it could interact with your medicines. Ask a doctor or pharmacist first if you are pregnant or breastfeeding, and do not give magnesium supplements to children without medical advice.

Magnesium has been studied for sleep in older adults with insomnia: in three small trials (151 people), the time to fall asleep was about 17 minutes shorter than with placebo, but the evidence was low to very low quality,6 and we did not find trials of magnesium supplements in people taking GLP-1 medications.

Shop Magnesium Glycinate →
From the Literature

Protein distribution may matter, but the evidence is limited. In a small crossover study of 8 healthy adults, spreading protein evenly across three meals gave 25% higher 24-hour muscle protein synthesis than eating most of it at dinner.19 A systematic review of 15 studies in healthy adults found an association between even protein distribution and higher muscle mass in 3 of 7 studies, and the evidence was insufficient for muscle strength or protein turnover.20 Neither looked at lean mass retention during calorie restriction or at people taking GLP-1 medications. Protein targets depend on kidney health and other conditions, so ask a clinician or dietitian.

Creatine has not been tested in people taking GLP-1 medications. A 2026 paper describes creatine as a biologically plausible but hypothesis-generating idea for GLP-1-associated muscle loss and states that no randomized clinical trial has directly evaluated it during GLP-1-based weight loss.21 In a meta-analysis of 26 trials, creatine raised blood creatinine (a marker doctors use to assess kidney function), but kidney filtration measured with a direct method did not change significantly; the authors judged this more likely to reflect altered creatinine metabolism than kidney injury.22 Tell your clinician if you take creatine before kidney blood tests, and ask before using it if you have kidney disease.

Low magnesium intake is common. About half of Americans (48%) consumed less than the required amount of magnesium from food in 2005–2006.15 This figure describes intake from food, not measured deficiency.

References and Notes

References: (1) Sievenpiper JL, et al. Obes Pillars. 2026;17:100228. PubMed · DOI (2) Mozaffarian D, et al. Am J Clin Nutr. 2025;122(1):344-367. PubMed · DOI (3) He L, et al. JAMA Intern Med. 2022;182(5):513-519. PubMed · DOI (4) Zhou Q, et al. Gut. 2019;68(6):996-1002. PubMed · DOI (5) Ferracioli-Oda E, et al. PLoS One. 2013;8(5):e63773. PubMed · DOI (6) Mah J, Pitre T. BMC Complement Med Ther. 2021;21(1):125. PubMed · DOI (7) Zhao JV, et al. J Nutr. 2023;153(10):2939-2950. PubMed · DOI (8) Dumitru CN, et al. Pharmaceuticals (Basel). 2026;19(8):1313. PubMed · DOI (9) Blais JE, et al. Drugs. 2023;83(5):403-427. PubMed · DOI (10) Ma J, et al. Phytomedicine. 2026;162:158782. PubMed · DOI (11) Chen Y, et al. Diabetes Metab Syndr Obes. 2025;18:3865-3881. PubMed · DOI (12) Doron S, Snydman DR. Clin Infect Dis. 2015;60 Suppl 2:S129-34. PubMed · DOI (13) Alshatari S, Ziarno M. Front Nutr. 2026;13:1895136. PubMed · DOI (14) Matek Saric M, et al. Nutrients. 2025;17(22):3626. PubMed · DOI (15) Rosanoff A, et al. Nutr Rev. 2012;70(3):153-64. PubMed · DOI (16) Firoz M, Graber M. Magnes Res. 2001;14(4):257-62. PubMed (17) Costello R, et al. Adv Nutr. 2023;14(5):973-982. PubMed · DOI (18) Vermeulen EA, Vervloet MG. Nutrients. 2023;15(3):547. PubMed · DOI (19) Mamerow MM, et al. J Nutr. 2014;144(6):876-80. PubMed · DOI (20) Jespersen SE, Agergaard J. Eur J Nutr. 2021;60(6):3185-3202. PubMed · DOI (21) Ostojic SM, Galyean S. Clin Nutr. 2026;66:106805. PubMed · DOI (22) de Souza Almeida A, et al. Int Urol Nephrol. 2026. PubMed · DOI

This issue is general information, not medical advice, and is not intended to diagnose, treat, cure or prevent any condition. Do not start, stop, reduce or change a prescribed medicine because of anything in this issue; ask your prescriber or pharmacist. Supplements are not suitable for everyone: ask a doctor or pharmacist before use if you take medicines, have kidney disease or diabetes, are pregnant or breastfeeding, or are immunocompromised, and do not give supplements to children without medical advice. Individual responses vary; the studies summarized report population-level findings, not guaranteed individual outcomes.

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The Kasivit Journal · Issue 1
May 12, 2026 · Kasivit Editorial Team