Thyroid UK
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Hi I hope someone might be able to give me some advice. Me and my girlfriend are trying for a baby but I have just found out my thyroid is under performing (9.6 somethings instead of 12 somethings I think). I read that this can affect my fertility and have done an over the counter fertility test and it said I have a low sperm count. Bit bummed about that. My doctor started me on 50mg levothyroxine two days ago, but he doesn't know anything about thyroids and fertility. Does anyone know how long it takes to start having a positive effect on sperm count (if that is actually the cause of the problem)? Please help.

10 Replies

Welcome to the forum, RootyTooty.

Hypothyroidism does cause fertility problems but fertility usually resolves after you are optimally medicated.

It takes 7-10 days for Levothyroxine to be absorbed  before it starts working and  it will take up to six weeks to feel the full impact of the dose.

You should have a follow up thyroid test 6-8 weeks after starting Levothyroxine.  Arrange an early morning and fasting (water only) blood draw when TSH is highest, and take Levothyroxine after your blood draw.

Most people will find symptoms resolve after their TSH drops to around 1.0 with FT4 in the upper range but symptoms can lag a couple of months behind good biochemistry.

For maximum absorption Levothyroxine should be taken with water 1 hour before or 2 hours after food and drink, 2 hours away from other medication and supplements, and 4 hours away from calcium, iron, vitamin D supplements and oestrogen.

Get into the habit of asking for a copy of your thyroid results and ranges (the figures in brackets after results) from your GP receptionist or from your GP when you see him/her so you can track your progress.  Post them in a new question for comment if you want interpretation of your results.

Most thyroid advice is directed at women but there is advice specifically for men in these links:


I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.


Thanks for your reply, I'm waiting for a referral to endocrine team so will hopefully get some more details on my levels. 


Welcome to our forum RootyTooty,

Low testosterone and probably LF (Leutinizing Hormone) are is common in men with low thyroid hormone.

Good advice given by Clutter above but just wanted to add  - ask your GP to test Vit B12, Vit D, folate and ferritin as many people with low thyroid hormone are deficient in these very nutrients required for good thyroid hormone synthesis.

Eating a healthy diet and reducing stress will help thyroid meds to work better and if you have thyroid antibodies, these must be kept low. 

If you post your thyroid hormone test results complete with ranges (numbers in brackets) in six weeks time, members will comment.



Thanks for your reply I will look into tests and supplements and vitamins when I meet the endocrine specialist. Thanks!

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Oh! A word of warning! Doctors know nothing about nutrition. They may or they may not do the tests, but they won't understand the results. Do not be taken in if they tell you vitamins and minerals are unimportant. They are very important! So, if you manage to get any tests done, post your results on here and we'll be able to tell you what they mean.

Welcome to the forum! :)


Thank you


Hi rootytooty, I didn't realise underactive thyroid could also impact male fertility.  I suppose it makes sense though. My husband and I also facing similar issues but the thyroid problem is on my side. I was diagnosed in Dec, but still feeling very symptomatic, so need to feel well again before I concentrate on fertility again. It takes a while to go through the process and get your levels right. Best of luck with the consultant. And lots of baby dust to you and girlfriend 


Thanks for your reply, sorry you are going through it too. Are you taking levothyroxine - have you felt any improvements? I've only ben taking it for 5 days. What are your symptoms?

I've been feeling run down for a while but put it down to stress due to my studies and some family problems.


I was started on 50mcg levothyroxine a day, and have had 2 dose increase since. When I first started taking medication after about a week or 2 I felt amazing, bags of energy, like a light had been turned on. I didn't realise how bad I had been before until that point. Like you put it down to work and stress. Then once my body got used to that dose I went down hill and started to get a whole host of symptoms; exhausted, dry hair, skin, nails breaking (not that you'll be to worried about that), losing more hair than normal, body aches - the worst is feeling exhausted for no reason. It's been the same with the dose increases a little better then symptoms return. I'm hoping that once I am on the right level of meds my symptoms should go, well that's what I am aiming for as can't cope feeling like this. I think overall I feel slightly worse now than before I started but maybe it's that things get worse before they get better and you just have to persever and get on the right meds. Also from reading stuff on here vitamins are important and you need to get your levels check but others will tell you about that. I am still very new to all this. 


How is everything going? I hope your levels have improved and you are feeling better?

I have had some good news, my girlfriend is now 14 weeks pregnant!

Still sorting out my levels and have posted my blood tests to hopefully get some advice on vitamins etc


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