I'm taking vitamin C supplements and desloratadine for my allergies.

I've heard some people saying that it's better to take your medicines right after eating because your body absorbs them better then.

I couldn't find any studies on the internet which would prove them either wrong or right.

So I'm still wondering whether my medicines will have a better effect if I consume them with food.

Will they really work better when taken with food? If so, why?

  • 1
    Welcome to MedicalSciences.SE! Please take the tour and read the help center. For reasons mentioned in this post and in How to Ask, we require prior research information when asking questions. See this list of helpful resources. Please help us to help you and edit your question to provide more information on what you have read on this subject, what made you ask this question, and any problems you are having understanding your research. If you found nothing, what did you Google?
    – Carey Gregory
    Mar 17, 2019 at 16:36
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    Depends entirely on the medication. Some meds require an empty stomach, others work better with food - you need to read about each medication to know its individual recommendation for administration. There is no concise, generic way to answer this, as the mechanisms for absorption involve many factors. I think as it is, this is not answerable.
    – DoctorWhom
    Mar 18, 2019 at 10:28
  • @DoctorWhom Contra: how you differentiate in your comment would be an excellent start of an answer. Main problem imo is lack of prior research. We should perhaps be more accepting of frame challenges? Mar 19, 2019 at 11:22

1 Answer 1


Desloratadin is slightly soluble in water and very soluble in ethanol. While that would often indicate an at least slightly better if time-delayed absorption with food, this is apparently not the case:

Following oral administration of desloratadine 5 mg once daily for 10 days to normal healthy volunteers, the mean time to maximum plasma concentrations (Tmax) occurred at approximately 3 hours post dose and mean steady state peak plasma concentrations (Cmax) and area under the concentration-time curve (AUC) of 4 ng/mL and 56.9 ng·hr/mL were observed, respectively.

Neither food nor grapefruit juice had an effect on the bioavailability (Cmax and AUC) of desloratadine.

R. Manivannan et al.: "Formulation Development and Evaluation of Desloratadine Tablets", International Journal of PharmTech Research CODEN (USA): IJPRIF ISSN : 0974-4304 Vol.2, No.3, pp 2101-2106, July-Sept 2010. (PDF)

  • Thank you for your answer! What about vitamin C? Mar 21, 2019 at 18:25
  • @HinkoPihPih Do you mean absorption of VitC alone w/wo food; or VitC in conjunction with Deslora regarding absorption? Mar 21, 2019 at 18:40
  • Vitamin C alone with and without food. Mar 21, 2019 at 18:47
  • That should really be a separate question then. As there are differences between isolated/synthetic and 'natural' etc. Mar 21, 2019 at 19:32

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