Sorry - I am afraid the short answer to that is there is no chemical to put on your body that has ever proved effective in stopping or discouraging bedbugs from having your blood as their dinner, should they have taken up residence in or near any bed you are going to sleep in whether at home or staying somewhere else.
One way that might however help is not to be naked when in bed. Cover as much of your body as possible, such as with tight fitting pyjamas and socks. But really the only sure way to avoid bedbug bites is to exterminate them from your home if they are there, and I have explained how you can best do that in other answers. Also if you stay in a hotel make sure it is not on record on hotel websites as having had a bedbug problem. Also have a very thorough check in your hotel room or cabin on a ship to ensure there are no signs of bedbugs having been there before getting into that bed to sleep.
Bedbug
You can buy over the counter flea repellents that come in a spray or in a cream. There is also natural remedies such as garlic and also applying apple cider vinegar over the whole body.
Gnat bites are generally harmless but can cause itching, redness, and swelling. In some cases, they may lead to a mild allergic reaction. It's important to avoid scratching the bites to prevent infection and use topical creams or antihistamines for relief.
To prevent no see um bites, you can wear long sleeves and pants, use insect repellent containing DEET, avoid being outdoors during dusk and dawn when they are most active, and use mosquito nets around sleeping areas.
Appendages
To protect yourself from black biting bugs while outdoors, you can wear long sleeves and pants, use insect repellent containing DEET, avoid areas with standing water, and check your body for bites after being outside.
The best treatment for ant bites when pregnant is to use Neosporin. If the bites are severe, you will need to visit your doctor for a prescription.
Adding yeast to a CO2 bedbug trap can enhance its effectiveness by producing more carbon dioxide, which attracts bedbugs. Yeast produces CO2 as it ferments, increasing the amount of this gas in the trap and making it more appealing to bedbugs.
No, it is not recommended to use native body wash on dogs for bathing. It is best to use products specifically designed for dogs to avoid skin irritation or other potential issues.
No you can not. Its only for ringworm and fungi related issues.
This is unlikely. You need to understand people do not normally carry bedbugs around with them. It isa bed not a person that gets infested with bedbugs! Thus whoever sleeps in an infested bed will have a bedbug problem only while they are using that bed, but when they get up and go elsewhere the bedbug problem no longer affects them. They may have bite marks on their body afterwards as a consequence of being bitten while in that bed but that does not mean they can pass their former bedbug problem to somebody else. If two people share use of an infested bed then both are equally likely to get bitten by one or more bedbugs while they are in that bed, and although this could happen during a hug, generally bedbugs only crawl on to you to have a meal when your body is still after detecting your sleeping CO2 breath. If you are making love your bodies will be moving around considerably so a bedbug is very unlikely to come on to you until later when it is safer for it to have its meal undisturbed.
Use insect repellent.