Hi, i take 40mg of propranolol a day, is it okay to take raspberry ketones?

No: Raspberry ketones are a fraud and can only harm you. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex, if you have sex. Get HPV vaccine.

OK but worthless: It is OK to take "raspberry ketones" if you are taking propanolol but there are absolutely no research studies showing that this product (which is not actually made from raspberries) has any benefit at all- see https://authoritynutrition.com/do-raspberry-ketones-work/ Presuming you want to lose weight see these articles for good advice: https://authoritynutrition.com/articles/weight-loss/